326results about "From frozen solutions" patented technology

The invention provides a crystal growth device and a crystal growth method, and solves the technical problems of low wafer utilization rate, low crystal growth speed, low efficiency, poor uniformity and the like in the existing chip manufacturing process. According to the invention, a traditional cylindrical ampoule structure is abandoned, and the annular ampoule design is innovatively adopted, so that the crystal grows into an inner hollow cylinder shape which is highly matched with the specification of a target wafer; the heater is arranged on the inner side of the ampoule, a traditional outer side heating mode is replaced, and heat is intensively acted on crystals in cooperation with an adjusting center of a heat preservation material during crystal growth, so that heat loss is reduced; the periphery of the heater is made of heat insulation materials, heat radiation leakage is effectively restrained, meanwhile, the ampoule supporting structure is adjusted, and the whole device is simple, low in cost and light in weight.

The invention relates to the technical field of crystal material preparation, in particular to a layered selenide Ge3Sb2Se5 semiconductor material and a preparation method thereof. The preparation method of the layered selenide Ge3Sb2Se5 semiconductor material comprises the following steps: grinding a Ge3Sb4Se7 material, putting the ground Ge3Sb4Se7 material into a quartz tube, adding iodine particles, performing vacuum packaging in the quartz tube, putting one end, with raw materials, of the quartz tube into a high-temperature region, and putting one end, without raw materials, of the quartz tube into a low-temperature region; raising the temperature to 400 + / -25 DEG C at the low-temperature region end and 500 + / -25 DEG C at the high-temperature region end, preserving heat for 7 days, and naturally cooling to room temperature to obtain the Ge3Sb2Se5 semiconductor material. The crystal structure of the Ge3Sb2Se5 semiconductor material belongs to an orthorhombic system, and the Ge3Sb2Se5 semiconductor material has the characteristics of low thermal conductivity and low resistivity. According to the preparation method disclosed by the invention, the Ge3Sb2Se5 semiconductor material can be stably prepared, and a material is provided for physical property research of the Ge3Sb2Se5 semiconductor material and preparation of semiconductor photoelectric devices and the like.

The invention discloses a nickel-based single-crystal high-temperature alloy with high structure stability and a preparation method thereof, and relates to the technical field of high-temperature alloys. The nickel-based single crystal high-temperature alloy provided by the invention is prepared from the following components in percentage by mass: 5 to 7 percent of Al, 7.5 to 10 percent of Co, 5 to 7 percent of Cr, 0.1 to 0.2 percent of Hf, 0 to 2 percent of Mo, 5.5 to 7.5 percent of Ta, 0 to 1 percent of Ti, 8 to 10 percent of W, 0.02 to 0.05 percent of C, 0.003 to 0.005 percent of B and the balance of Ni. According to the invention, by controlling the ratio of elements and avoiding the addition of Re, the precipitation temperature of a harmful TCP phase is obviously reduced to about 840 DEG C on the basis of maintaining a sufficient solid solution strengthening effect, and the long-term stability of the structure is greatly improved. The high-temperature mechanical property of the alloy provided by the invention reaches the level equivalent to that of a traditional Re-containing second-generation single-crystal alloy and is remarkably superior to that of foreign Re-free single-crystal alloys MD2 and Rene N500, and the nickel-based single-crystal high-temperature alloy with high structure stability successfully realizes the unification of low cost and high performance, and is suitable for industrial production. And a reliable material solution is provided for manufacturing the heavy-duty gas turbine blade with higher market competitiveness.

The invention discloses a Bridgman method growth gallium oxide single crystal abnormity detection method based on multi-mode perception, and relates to the technical field of single crystal preparation, and the method comprises the following steps: S1, collecting optical signals of a melt surface area in a Bridgman method growth gallium oxide single crystal process through a sensor array, synchronously acquiring temperature field data or infrared thermal image data of the region; the method comprises the following steps: acquiring an original spectral data set covering a local area according to a radiation signal under a micron-order spatial resolution, and obtaining initial radiation distribution information; according to the anomaly detection method for growing the gallium oxide single crystal by the Bridgman method based on multi-mode perception, dynamic tracking and accurate positioning of component anomaly in the growth process of the Bridgman method are realized, and an effective technical means is provided for improving the growth quality of the gallium oxide single crystal, reducing crystal defects and improving the process control capability.

The invention discloses an oxygen-enriched destressing crystal growth method and a crystal growth furnace, and relates to the technical field of crystal growth, and the oxygen-enriched destressing crystal growth method comprises the following steps: step 1, pre-treating a PMNT polycrystal material, and putting the pretreated PMNT polycrystal material into a crucible; 2, pre-flushing the growth furnace and creating an oxygen partial pressure environment; 3, raising the temperature in the growth furnace to melt and homogenize the PMNT polycrystal material in the crucible; step 4, the crucible moves downwards for directional solidification of the crystal, a solid-liquid interface is formed and stably moves upwards, and in the process, a dynamic regulation and control strategy is adopted in the growth furnace to control an oxygen-enriched environment to promote crystal growth, so that the crystal digests growth stress in the growth process, and formation of oxygen vacancies is inhibited; and step 5, after crystal growth is finished, gradient cooling is performed to room temperature in an oxygen-enriched environment, and a crystal ingot is obtained. Oxygen is used as a regulation and control tool, the stress problem caused by oxygen vacancy is physically solved, the color center and performance problems caused by oxygen vacancy are chemically solved, and the crystal growth quality is improved.

An automatic temperature control method for a crystal growth device, a system, and a device. The method is used for a crystal growth device. The crystal growth device comprises a main control heating body and an auxiliary control heating body, wherein the main control heating body is used for controlling a high-temperature interval of the growth device, and the auxiliary control heating body is used for controlling a low-temperature interval of the growth device. The automatic temperature control method comprises: acquiring a growth parameter of a crystal growth solid-liquid interface, wherein the growth parameter is used for representing the growth state of a crystal; calculating a temperature adjustment amount for the main control heating body on the basis of the offset of the growth parameter by using a first multi-stage automatic temperature control algorithm, and calculating a temperature difference adjustment amount for the auxiliary control heating body and the main control heating body on the basis of the offset of the growth parameter by using a second multi-stage automatic temperature control algorithm; and adjusting the main control heating body on the basis of the temperature adjustment amount for the main control heating body, and adjusting the auxiliary control heating body on the basis of the temperature adjustment amount for the main control heating body and the temperature difference adjustment amount for the auxiliary control heating body and the main control heating body.

The invention discloses a 7N single crystal copper preparation process based on zone melting and crystal orientation control, which specifically comprises the following steps: S1, raw material pretreatment: purifying 4N copper to 5N grade by adopting electrolytic refining of a nitric acid system, and the carbon content after acid pickling is less than or equal to 1ppm; the invention relates to the technical field of metal material preparation. According to the 7N single crystal copper preparation process based on zone melting and crystal orientation control, impurities in a material are redistributed in a melting zone through local heating, so that separation and removal of the impurities are achieved, in single crystal copper preparation, zone melting can remarkably reduce the content of the impurities in copper, the purity of the copper is improved, and the yield of the 7N single crystal copper is improved. By accurately controlling parameters such as the temperature gradient and the cooling rate in the smelting and solidification process, optimization of crystal orientation is achieved, single crystal copper with an ideal crystal structure can be obtained, the performance of the single crystal copper is improved, and impurities can be removed and crystal defects can be reduced through zone smelting; and crystal orientation control can optimize the crystal structure and improve the performance.

The invention discloses a high-temperature alloy turbine blade directional solidification method based on multistage dynamic gas protection control. The high-temperature alloy turbine blade directional solidification method comprises the following steps that a high-temperature alloy mother alloy material is put into a crucible; filling inert gas to a preset pressure, heating the crucible, heating to a preset temperature, and keeping the temperature to ensure that the alloy liquid is liquefied; continuously filling inert gas to preset pressure and then refining, wherein a vibration generator generates a magnetic field in the refining process to carry out electromagnetic vibration on the alloy liquid; continuously filling inert gas to preset pressure, and then transferring the crucible; inert gas is continuously filled to preset pressure, then the crucible is tilted, pouring is conducted, and in the pouring process, a gas purging device sprays the inert gas to conduct purging protection on the alloy liquid; and continuously filling inert gas to preset pressure, and pulling the shell to finish the directional solidification process. The method can reduce the gas content in the melt, prevent the melt from being oxidized, promote the removal of a surface oxidation film, reduce pores and oxidation film inclusion, and improve the purity, mechanical properties and yield of the casting.

A multi-component rare-earth garnet optical material containing at least three different rare-earth elements and optionally activator ions is described. The optical material includes a rare-earth garnet scintillator. A method for preparing powders, ceramics, and single crystals of the optical material is also described. Further, a radiation detector including a rare-earth garnet scintillator is described.

The invention discloses a growth method of an alloy metal single crystal, which comprises the following steps: loading an alloy raw material containing a target alloy metal single crystal into a crucible, placing the crucible in a vacuum furnace, purifying the atmosphere in the vacuum furnace, and filling protective gas; heating until the alloy raw material is fully molten, filling set gas to normal pressure, and keeping the temperature to enable the molten liquid to reach a saturated state; cooling at a set cooling rate to form crystals on the surface of the melt; and naturally cooling to room temperature, taking out the crucible, and transferring and treating the surface crystal to obtain the alloy metal single crystal. A set gas is introduced into alloy melt or a crucible material is used for dissolution, two-dimensional single crystals are formed on the surface of the melt in the cooling process, and the two-dimensional single crystals serve as a template to induce metal single crystals to grow from the surface. The method is simple in principle, novel and easy to operate.

The application discloses a kind of high plasticity single crystal high-entropy high-temperature alloy without Fe and Ti and a preparation method thereof.The chemical composition of the alloy includes Co, Ni, Cr, Al, Ta, Mo and W seven elements, and the atomic percentage of each element is Co 35-45at%, Ni 30-40at%, Cr 3-5at%, Al 10-13at%, Ta 1-4at%, Mo 1-3ar% and W 3-5at%.The preparation method includes the following steps: sequentially putting elemental Co, Ni, Cr, Ta, Mo and W into the crucible of vacuum induction melting furnace for heating and melting, adding elemental Al when the temperature rises to the refining temperature, and pouring into master alloy ingot;using high-speed solidification Bridgeman method and seed crystal method to prepare single crystal high-entropy high-temperature alloy test rod with <001> grain orientation;and sequentially carrying out solid solution treatment, primary aging and secondary aging on the single crystal high-entropy high-temperature alloy test rod, to obtain the high plasticity single crystal high-entropy high-temperature alloy without Fe and Ti.The single crystal high-entropy high-temperature alloy of the application has the advantages of high-entropy alloy and single crystal high-temperature alloy, and has excellent room temperature and high temperature mechanical properties.

The application belongs to the technical field of communication automation, and discloses a high-efficiency preparation process implementation method of semiconductor silicon carbide material based on a liquefaction method. The application aims at the core pain points of preparing semiconductor silicon carbide material by the liquefaction method, and constructs three core modules of raw material liquefaction precision regulation and control, silicon carbide crystallization directional induction and preparation process multi-field synergistic optimization, covering the whole process preparation of silicon carbide from raw material pretreatment, liquefaction reaction to crystallization forming. By adopting the cores of raw material component homogenization liquefaction regulation and control, silicon carbide crystal nucleus directional growth induction and temperature-pressure-concentration multi-field synergistic optimization, the technical bottlenecks of traditional liquefaction method preparation process, i.e. "raw material liquefaction is uneven, crystallization orientation is disordered and multi-field regulation and cooperation is poor", are broken through, the uniform liquefaction of raw materials, the directional growth of silicon carbide crystals and the high-purity forming are realized, the crystal quality, purity and preparation efficiency of semiconductor silicon carbide material are significantly improved, and the high-performance material demand of the third-generation semiconductor power device and high-frequency device is adapted.

The application discloses a kind of second generation nickel-based single crystal superalloy recrystallization defect simulation and control method.The method steps are: according to sample preparation wax mold, after sand blasting, dry baking, manufacture ceramic shell;Through directional solidification preparation second generation nickel-based single crystal superalloy sample, control pulling speed, holding temperature and temperature gradient and other parameters;According to service condition preparation sample, simulate stress loading, in combination with heat treatment simulate actual service environment;Using electron backscattering diffraction and X-CT imaging, characterize recrystallization grain orientation distribution, three-dimensional morphology, content and thickness.Process parameter-defect characteristic mapping relationship is established, the stress distribution characteristics during preparation are clarified, the ceramic shell and preparation process are feedback controlled, and the control of recrystallization defects is realized.The application simulates the actual service environment of high-temperature alloy blade, and restores the performance of recrystallization defect sample in actual service environment.The application provides an experimental reproduction method and effective process control strategy for recrystallization defect research.

This invention discloses a samarium-lanthanum co-doped calcium oxyborate yttrium nonlinear optical crystal material, its preparation method, and its applications. The samarium-lanthanum co-doped calcium oxyborate yttrium nonlinear optical crystal material belongs to the monoclinic crystal system, has a space group of Cm, and a chemical formula of Sm. 0.3 La 0.1 :Y 0.6 Ca4O(BO3)3 has a second harmonic response intensity of 0.89 × KDP, and exhibits transmittance exceeding 80% in the 500–1000 nm and 1600–2400 nm wavelength ranges. It also has a strong absorption peak in the 1000–1600 nm wavelength range. Therefore, the samarium-lanthanum co-doped calcium oxyborate yttrium nonlinear optical crystal can be considered as a nonlinear optical crystal material with broad application prospects in the field of optics.

The application provides a device and method for growing 6-inch ultra-low dislocation germanium single crystal by VGF+VB method, and belongs to the technical field of semiconductor crystal growth equipment. The device comprises a furnace body, at least six segments of independent temperature control heaters arranged in the furnace body along an axial direction, a flexible adjustable heat insulation structure, a PBN crucible system for loading seeds and raw materials, and a precision lifting device for realizing relative movement between the crucible and the furnace body. An accurate axial temperature gradient is constructed and moved by the multiple independent heaters, the radial heat loss is controlled by the adjustable heat insulation structure, and the multiple variable decoupling control technology is used to cooperatively and accurately control each temperature zone, so that the crystal growth dislocation, thermal stress and the solid-liquid interface shape are accurately controlled, and the high-efficiency, high-quality and ultra-low dislocation density growth of the 6-inch germanium single crystal is realized.

To provide an apparatus for manufacturing oxide single crystals, a method for manufacturing gallium oxide single crystals using the apparatus, and a gallium oxide single crystal manufactured thereby. [Solution] By applying a method that uses the oxide pellet itself, which is to be made into a single crystal, as the crucible without using a separate crucible, the problem of impurities entering due to the crucible is minimized. Furthermore, by applying a method that mixes hydrocarbon fuel gas and oxygen gas and generates heat using a flame, the growth atmosphere for the oxide single crystal can be maintained in a high-oxygen atmosphere, enabling the production of high-quality oxide single crystals with few defects.

The invention relates to a sapphire single crystal (4) and a method and apparatus (1) for producing it, wherein the sapphire single crystal (4) comprises a plurality of layers (11) arranged in a C-axis (7), wherein each layer (11) has a cross-sectional topography (12), wherein the cross-sectional topographies (12) of the layers (11) repeat with respect to geometric patterns (13) formed in the cross-sectional topographies (12), wherein the geometric patterns (13) are predominantly composed of polygonal rings, in particular of concentric hexagonal or concentric hexagonal rings.

The invention belongs to the technical field of crystal growth, and provides a growth method of a large-size semi-insulating indium phosphide single crystal. According to the VGF growth method of the indium phosphide single crystal, a thermal field structure is optimized, six temperature zones are set, and the temperature of each temperature zone is controlled; the method comprises the following steps: preparing an indium phosphide polycrystalline column, then charging and doping, respectively placing dopants in at least three axial partitions of the indium phosphide polycrystalline column, regulating the temperature before crystal growth, firstly regulating the temperature of an equal-diameter region, then regulating the temperature of a head seed crystal region, carrying out crystal growth, and respectively controlling the specific growth rates of seeding, shouldering, equal-diameter and ending stages; and finally, annealing to prepare the indium phosphide single crystal with the size greater than or equal to 6.5 inches. According to the invention, the preparation of the large-size semi-insulating indium phosphide single crystal with high quality and high yield is realized.

The application belongs to the technical field of laser materials, and relates to a holmium-praseodymium-scandium doped composite calcium fluoride single crystal as well as a preparation method and application thereof. 0.01 Pr x Sc y Ca 0.99‑x‑y F 2.01+x+y , wherein 0.005 <= x <= 0.015, 0.005 <= y <= 0.05; the crystal is obtained by growing the crystal in a vacuum environment through a temperature gradient method. Compared with the prior art, the application can realize high-efficiency laser output in a 2-3 mu m mid-infrared wave band, the grown crystal has the characteristics of high thermal conductivity, high chemical stability, high transmittance and high quality, and has the advantages of high gain bandwidth, high gain cross section, high power and high slope efficiency in the mid-infrared wave band, and has significant advantages in the fields of environmental monitoring, industrial processing, national defense and safety.

The present application relates to a kind of Bi-doped rare earth iron garnet body single crystal growth techniques without substrate, comprising the following steps: raw material preparation, melt preparation, melt is cooled to crystal growth temperature, after melt temperature stabilizes, slowly lower the seed crystal rod installed with seed crystal, with melt, seed crystal rotates at a certain speed;During growth, crystal growth is carried out according to the set variable speed cooling curve, and block crystal is obtained after growing for a period of time;Block crystal is pulled out from melt, and slowly cooled to room temperature, and Bi-doped rare earth iron garnet body single crystal is obtained.The present application obtains large-size block single crystal, gets rid of the dependence of existing Faraday optical rotator growth on substrate, and reduces production cost.The present application can obtain Faraday optical rotator which is thinner than existing product thickness at the same wavelength, further reducing the volume.Moreover, multiple surfaces are simultaneously grown, and larger size crystal is obtained.

The utility model relates to the technical field of gallium oxide crystal growth, and discloses a crucible structure for growing a gallium oxide single crystal by a VB method, which comprises a crucible shell, a seed crystal cavity, a diameter-expanding cavity, a diameter-reducing cavity, a shoulder-expanding cavity and an equal-diameter cavity, the seed crystal cavity, the diameter-expanding cavity, the diameter-reducing cavity, the shoulder-expanding cavity and the equal-diameter cavity are arranged in the crucible shell, the seed crystal cavity is arranged at one end of the crucible shell, and the diameter-reducing cavity is arranged at the other end of the crucible shell. One end of the seed crystal cavity is closed, the other end of the seed crystal cavity is connected with the diameter-expanding cavity, the diameter-expanding cavity is connected with the diameter-reducing cavity, the diameter-reducing cavity is connected with the shoulder-expanding cavity, the shoulder-expanding cavity is connected with the equal-diameter cavity, and the other end of the equal-diameter cavity is open. Through reasonable design of a gallium oxide growth technology, the crucible shell, the seed crystal cavity, the diameter-expanding cavity, the diameter-reducing cavity, the shoulder-expanding cavity and the equal-diameter cavity are adopted, so that gallium oxide crystals can be separated from the crucible wall during growth and cooling, dislocation proliferation and twin crystal structures are not easy to appear, the crystal dislocation density is reduced, and the performance of a semiconductor chip is improved. The crucible structure can be used for preparing cylindrical gallium oxide single crystals with low dislocation density.

The indium phosphide single-crystal substrate has a circular main surface, and the main surface is virtually divided with a square grid at a grid interval of 1 mm. The square grid is composed of a plurality of grid points present along a first direction and a second direction orthogonal to the first direction. A set consisting of dislocation densities measured at the respective grid points has a first whole-surface mean as the mean of the set and a first whole-surface standard deviation as the standard deviation of the set, and each of the dislocation densities is classified as any one of a first level, a second level, and a third level. The grid points each determined to have a dislocation density classified as the second level are present in a region between an outline of a first square region and an outline of a second square region.

The invention discloses a method for manufacturing a molybdenum-rhenium alloy single crystal bar through an electric arc fuse additive. The method comprises the following steps that firstly, molybdenum powder and rhenium powder are mixed; 2, cold isostatic pressing; 3, sintering; 4, rotary swaging and wiredrawing; 5, alkali washing and ethanol cleaning; 6, the clean molybdenum-rhenium alloy wire is put into an electric arc fuse wire additive manufacturing molybdenum-rhenium alloy single crystal device; 7, fixing molybdenum-rhenium alloy single crystal seed crystals; 8, introducing cooling water; and ninthly, argon is introduced for gas washing, electric arc fuse wire additive manufacturing is conducted, and the molybdenum-rhenium alloy single crystal bar is obtained. The molybdenum powder and the rhenium powder are prepared into the molybdenum-rhenium alloy wire, then the molybdenum-rhenium alloy single crystal device is matched with the molybdenum-rhenium alloy single crystal seed crystals and the electric arc fuse wire additive manufacturing, electric arc fuse wire additive manufacturing is carried out, oriented surface growth of the molybdenum-rhenium alloy single crystal rod is achieved, preparation of the molybdenum-rhenium alloy single crystal rod is achieved, and the production efficiency of the molybdenum-rhenium alloy single crystal rod is improved. The method is suitable for preparing the molybdenum-rhenium alloy single crystal bar in the technical field of directional solidification of refractory alloy, the raw material utilization rate is increased, and the cost is reduced.

The invention provides an N-type bismuth-antimony alloy polycrystalline thermoelectric material as well as a preparation method and application thereof. The preparation method comprises the following steps: sealing Bi and Sb in a quartz tube according to a stoichiometric ratio, and smelting to obtain an ingot material; loading the ingot into a quartz tube with a nozzle, heating and melting the ingot, spraying the ingot into a metal mold through the nozzle, and carrying out ultrafast quenching to obtain an alloy bar; and then the alloy bar is subjected to annealing treatment. According to the preparation method, the bismuth-antimony alloy is prepared by adopting an ultrafast quenching technology and combining with annealing treatment for the first time, and the N-type bismuth-antimony alloy polycrystalline thermoelectric material with highly uniform components and large grain size is obtained. According to the method, the thermodynamic characteristics of the liquid phase are reserved, the oxidation problem is avoided, and the method is very beneficial to the realization of the optimal electron and lattice transport performance, so that the industrialization of the Bi-Sb thermoelectric material becomes possible, and the Bi-Sb thermoelectric material has an opportunity to enter the market and be used for preparing high-performance thermoelectric devices.

The application discloses a material for connecting single-crystal superalloy and polycrystal superalloy and a preparation and use method thereof, and the material comprises low-melting-point Ni-Ti alloy powder and high-melting-point Ni-based alloy powder. The material can realize rapid high-performance connection of the single-crystal superalloy and the polycrystal superalloy. The application belongs to the technical field of alloy material connection.

The invention provides a double-layer crucible. The double-layer crucible comprises an outer circular tube-shaped container, an inner circular tube-shaped container and a T-shaped cylindrical plug, the double-layer structure can solve the problems of raw material loss and proportion imbalance caused in the process of filling the raw materials into the crucible, and the perovskite crystal which can be used for normal-temperature nuclear radiation detection can be industrially prepared by using the Bridgman method in an economic mode. And a vacuum cavity can be provided as a temperature buffer area, so that the thermal disturbance of a crystal growth interface is reduced. The method can also be used for atmosphere regulation and control, and component segregation caused by element volatilization is relieved. The invention also provides a method for preparing a perovskite polycrystal material and a method for preparing a perovskite single crystal.

The utility model discloses a thermal field structure of a gallium oxide crystal growing furnace, which relates to the technical field of crystal growth and comprises a crystal growing furnace, a vertical channel hole communicated with a furnace chamber is arranged at the bottom of the crystal growing furnace; the silicon molybdenum rod heater is arranged in the furnace chamber; the crucible can penetrate through the vertical channel hole to enter the furnace chamber; the lifting driving mechanism is used for driving the crucible to enter the furnace chamber through the vertical channel hole or leave the furnace chamber through the vertical channel hole; the heat preservation element comprises a heat preservation partition plate and a heat preservation column. After the crucible is withdrawn from the furnace chamber, the heat-insulating partition plate can cover the top end of the vertical channel hole, so that on one hand, the temperatures of the crucible and crystals are effectively reduced, and the quality of the crystals is improved; on the other hand, heat in the furnace chamber can be effectively prevented from being dissipated through the vertical channel holes, the temperature in the furnace is more stable, and the temperature of the silicon-molybdenum rod heater in the discharging stage is maintained, so that the silicon-molybdenum rod heater is prevented from cracking due to the fact that the temperature is reduced to a cold brittle state.

This invention discloses a barium borate crystal, its preparation method, and its applications. The barium borate crystal has the chemical formula Ba₂BeB₂O₆, a non-centrosymmetric structure, belongs to the orthorhombic crystal system, has the space group Pca₂₁, and its cell parameters are α = 90°, β = 90°, and γ = 90°. This barium borate crystal exhibits extremely low birefringence from the ultraviolet to the infrared band, and its extremely low birefringence supports its application on zero-order glass slides.

The present disclosure provides a crucible assembly for producing a cathode active material. The crucible assembly includes a first crucible having an open top and an internal space and a second crucible disposed below the first crucible and having an incision groove with an open area at an upper portion of each sidewall.